This invention relates to valve assemblies.
The invention is more particularly concerned with spool valve assemblies of the kind for making interconnection of an outlet with one of two or more inlets at different pressures.
Spool valves have an outer housing provided with inlet and outlet ports in its wall at locations spaced along its length. A valve member is movable along the length of the housing and has several annular sealing flanges that slide over the wall to provide a fluid-tight seal. By appropriately positioning the sealing flanges fluid can be directed around the valve body between the desired ports.
The problem with such valves is that they are prone to leakage between the sealing flanges and the wall of the housing. This can be an especial problem where fluids are supplied at high pressure or where the sealing flanges have become worn or otherwise degraded after prolonged use.